1. Field of the Invention
The invention relates generally to devices and systems for dispensing pesticides.
2. Description of the Related Art
Mosquitoes and other flying pests are a significant problem in most parts of the United States. These insects not only create a hazard for livestock and farm animals, but also for humans in residential areas. Mosquitoes are, for example, the primary carriers of West Nile virus. Personal sprays and citronella candles and torches are often used to combat the pests. However, such measures are often inadequate during certain times of the year when mosquito activity is high. Propane-based attractor devices are also known, but their effectiveness is debatable.
U.S. Pat. No. 3,889,881 issued to Cunningham et al. describes a system for dispensing pesticides, typically in animal husbandry facilities. Cunningham employs a fluid reservoir that contains a liquid insecticide mixed with water. The reservoir is operably interconnected with a pump and motor that draws the water/insecticide mixture from the reservoir and transmits it along conduits to several nozzles, where the mixture is dispersed into and around chicken coops and the like.
Cunningham's system has a number of drawbacks. The system relies upon a return conduit to create turbulence within the reservoir so that the insecticide will be adequately mixed with the water within which it is suspended. In practice, however, such an arrangement is insufficient to create adequate turbulence and mixing. Even with an increase in pump capacity and tubing size, the line losses along the conduits create such a drop in fluid velocity, that the fluid reentering the reservoir is slowed too greatly to be effective in mixing. As a result of the inadequate mixing, the insecticide mixture that is dispersed from the nozzles may be too diluted to be effective in controlling the insects. At the very least, the mixture will be inconsistent throughout use. Because of the inadequate mixing problem, the concentration of insecticide needed for the system to be effective is quite high. There is, therefore, some waste of this somewhat costly insecticide. Further, Cunningham's system is not suitable for use with fluid mixtures that contain microencapsulated insecticides, which are fluid insecticides that contain small capsules or pellets (microcapsules) of insecticide agent in suspension. Inadequate mixing leaves a significant amount of the microcapsules inside the fluid reservoir and does not effectively transmit them to the nozzles. Microencapsulated insecticides have additional benefits that cannot be realized by a system that is incapable of effectively dispensing them. Other fluid insecticide distribution systems have similar drawbacks.
The present invention is directed to overcoming the problems of the prior art.